North Korea has restored part of a missile launch site it began to dismantle after a first summit with US President Donald Trump last year, in a move the United States has warned could lead to sanctions against them being “ramped up”.

South Korea’s Yonhap News Agency on Tuesday quoted lawmakers briefed by South Korea’s National Intelligence Service (NIS) as saying that the work was taking place at the Tongchang-ri launch site and involved replacing a roof and a door at the facility.

Satellite images seen by 38 North, a Washington-based North Korea thinktank, showed that structures on the launch pad had been rebuilt sometime between 16 February and 2 March.